package generics;

import java.util.Random;

//: generics/LinkedStack.java
// A stack implemented with an internal linked structure.

public class LinkedStack<T> {
	private class Node{
		T item;
		private Node next;
		public Node(){
			item = null;
			next = null;
		}
		public Node(T item, Node next){
			this.item = item;
			this.next = next;
		}
		public boolean end(){
			return item == null && next == null;
		}
	}
	private Node top = new Node();
	public void push(T item){
		top = new Node(item, top);
	}
	public T pop(){
		T result = top.item;
		if(!top.end())
			top = top.next;
		return result;
	}
	public static void main(String[] args) {
	    LinkedStack<String> lss = new LinkedStack<String>();
	    for(String s : "Phasers on stun!".split(" "))
	      lss.push(s);
	    String s;
	    while((s = lss.pop()) != null)
	      System.out.println(s);
	    Random r = new Random(47);
	    System.out.println(r.nextInt(40));
	  }
} /*
	 * Output: stun! on Phasers
	 */// :~
